1. Field
The present invention pertains to the field of LED lights and more specifically to a LED lighting fixture and components, universal mounting bracket and a method to control a lighting system.
2. Background
The ambient LED market is growing rapidly due to the promise of low power consumption and long life versus conventional lighting sources such as incandescent, fluorescent, and high intensity discharge. The new LED paradigm presents a challenge for all conventional lighting fixture manufacturers that are used to buying pre-manufactured lamps and ballasts (power conditioners) as a system.
Many entered the world of electronics and developed proprietary printed circuit boards to support the light emitting diodes that they purchased separately along with custom made LED drivers (power conditioners). This requires a level of expertise that is unfamiliar to most fixture manufacturers who are used to building housings and opticals around lamps and ballasts purchased from others. For success in the LED world, a level of competence must be gained in the critical areas of electronics design & thermal engineering. Even the optical output (lambertian distribution) of the LEDs is very different from the conventional light sources listed above. Introducing more complexity to fixture design represents a higher risk of failure unless handled properly. Some have done this well and some have not.
Recently, a number of tier 1 light emitting diode manufacturers have come out with complete systems which are similar to conventional models. You can purchase pre-manufactured printed circuit boards (PCB's) that already have the LED's mounted along with the requisite drivers and cabling to operate them within specifications given. Design guides are provided to facilitate successful implementation. This greatly reduces the risk and barrier to entry for conventional lighting fixture manufacturers to offer LED based product.
One such product is the Fortimo® system that is offered by Philips®. This is a family of products that comprise LED PCB's of varying length and lumen output as well as various drivers and cable sets that allow connection from driver to PCB and between PCB to PCB. The Fortimo design guide provides recommended installation methods to insure that the product performs according to specifications.
The suggested method of installing the LED PCB modules in the design guide and sales literature is to affix the PCB back onto a horizontal metal substrate (either steel or aluminum) with LEDs facing down using miniature screws. It is also recommended to apply thermal paste to the back of the PCB prior to fastening to the substrate in order to facilitate heat dissipation. In the world of LEDs, overcoming heat buildup at the diode is paramount to success. The prospect of affixing thousands of miniature screws and applying messy thermal paste represents significant assembly line time.
We decided to approach this technology from a fresh perspective. The first order was to determine exactly what thermal properties the LED PCB modules present. Our study revealed that the lowest thermal resistance occurs on the front face of the PCB that supports the LEDs as opposed to the back. We also discovered that if we oriented the boards vertically as opposed to horizontally we enjoy a significant thermal advantage. Further, since the heat transfer from the PCB backing is limited, the opportunity to position boards back to back became a good option.
Our next goal was to create a method to affix the boards without the requirement of miniature screws and thermal paste. Ideally, we wanted a way to eliminate the need for tools that could significantly increase assembly line speed. The result of our design efforts is the Vertikuhl™ system. This method creates a sandwich where the back to back PCB's are separated by a metal bracket and are also secured in place by metal snap on skins. The center bracket has features that allow for precision placement of the PCB's prior to the snap on application of the thermal skins. The assembler can now easily and consistently place the LED PCB modules on top of the center bracket which lay horizontally on the work table. Once in place, a metal skin snaps over the module face by means of punch outs on the skin and correlated lances that are located on the center bracket. Note that the skin also has punch outs that correspond to LED and other electronic part locations that are raised off of the PCB face. After complete, the assembly is turned over and the process repeated for the opposing side.
Background for Semble™ LED Lamp Assembly
Lighting based LED products are proliferating the market for every conceivable lighting application. Some products are being offered as direct conventional lamp (bulb) replacements such as LED lamps to replace incandescent spin-ins for downlighting (potlights) or track lighting. Others have been made to replace fluorescent lamps. Most of these forms have been targeted towards lower lumen output applications. In the case of lower wattage fluorescent replacements, the LED lamp manufacturers place LED PCB strips in a linear fashion within a recognizable fluorescent tube shape and use regular fluorescent lamp sockets. The thermal and directional nature of these lamps present some performance challenges in terms of limits to lumen output vs. MTBF.
For higher lumen applications such as parking lots and warehouses, lighting manufacturers have trended towards the creation of proprietary LED PCB arrays. The manufacturer purchases individual LEDs and has them placed on a custom PCB. Sometimes these are modular, others are more or less permanent.
Our desire was to create a universal lamp platform (Semble™) that would incorporate our Vertikuhl™ technology and requisite optical elements while allowing for tool-less replacement and optional adjustability. Vertikuhl™ creates unitized high or low lumen packages that can be correlated to existing lamp technologies. Vertikuhl™ light output is directionally driven (lambertian distribution) at 90 and 270 degrees from nadir. By itself, it does not fit many applications, but coupled with an efficient light delivery optical system, it can become extremely useful in a wide variety of applications.
Conventional light source technologies have allowed for lamps to be either screwed in or plugged in without the need for tools. This is what consumers are used to. While LED promises long life, the reality is that sometimes long life will not be experienced. Many factors can lead to significantly shortened MTBF such as high thermal environments, defective components or product assemblies, site specific power problems, etc. Besides being familiar, it is desirable for LED light sources to be replaceable without the requirement for tools.
As opposed to conventional light sources that provide 360 degree light dispersion, LEDs send light directionally in a lambertian distribution pattern. This means that either the LED array physically face the task area directly or a means of collecting and sending light to desired areas is required. A number of options can be used for this purpose such as reflective or refractive media. For an optimal degree of flexibility it is desirable to further allow for rotation of the Semble™ lamps whereby they can be aimed at the specific task area requiring light.
End caps were created to snap and lock onto the Vertikuhl™ ends without the need for tools. Further, chamfered recesses were created to fit over optical elements such as highly reflective polished aluminum reflectors or formed/injection molded/extruded plastic refractors. Specific arms were designed to allow for the end caps to be snapped into place within formed metal (or other) structures that serve to hold the whole assembly in place within a fixture body or to a building surface. The arms may also be squeezed together by hand to allow for easy removal. Formed processes within the end caps were created to support axles that would allow rotation of the complete assembly.
Background for AIOS Dimming™—Method to Control a Lighting System
Ideally, the most efficient lighting system would deliver the right type, quality, and amount of light, only when it is needed. This discussion considers the “amount” of light and “when” it is needed which is the domain of lighting controls.
In an effort to curtail power consumption from lighting systems, scientists have developed new light sources such as LED as well as a myriad of lighting controls that turn OFF or DIM down light intensity to save power. The following provides features and benefits of each control strategy along with limitations.
Occupancy Sensors are used to detect human presence within a space. They incorporate single or multiple technologies (i.e. Passive Infra-red or Ultrasonic) to sense motion and turn ON lights when a space is occupied. Some have sensitivity adjustments and most have an adjustable time delay (i.e. 30 seconds to 30 minutes). Every time the sensor sees someone it resets an internal timer. When no motion is detected and the timer runs out, the lights are turned OFF. Some sensors are independent and some control single or multiple circuits of lighting while others are mounted to light fixtures directly. There are some sensors that offer photo sensing and allow for lights to be turned OFF or ON at a measured threshold of natural day light. Other options may allow for separate 2 circuit control (i.e. Both circuits sensed vs. one sensed and one bypassed), alternating circuit control (i.e. To allow even burn times for multiple ballast/lamp fluorescent fixtures), and cold room use. Sensors are available for a wide variety of space dimensions such as offices, classrooms, and warehouses, to name a few. Occupancy sensors simply and affordably control lights, but they are limited to an ON/OFF function unless they are used within a larger lighting control system with light fixtures that are dimmable. Many applications cannot have lighting turned completely OFF such as retail, public spaces, and fabrication areas with dangerous equipment. Unfortunately when dimming is desired or required the systems become cost prohibitive and complex.
Photo Sensors are used to turn artificial lighting OFF or to DIM down and up based on how much natural light is present. The successful incorporation of this technology has been a challenge. For common area street lighting and parking it is accepted that when the sun comes up the lights go OFF and when the sun goes down the lights go ON. However, when you are controlling personal spaces, not everyone wishes to have their lights turn OFF and ON automatically when they are in the space. This has led to a lot of disconnections after installation. Control systems have been created to allow lighting to DIM down and up gradually which has seen more success, but as with occupancy sensing, this becomes much more expensive and complex which limits adoption.
Lighting control systems or centralized control systems incorporate multiple control strategies and use computers to turn ON, OFF, or DIM lighting fixtures based on programming inputs. These systems may hold intelligence within one computer or may broadly distribute intelligence via programmable chipsets that reside in smart switching panels or ballasts which receive instructions from the computer and keep memory of the instructions to be performed independently. By programming you can set outputs based on schedules that must be created or on inputs that are received from occupancy sensors, photo sensors, manual switches, personal computers, or even from another control system such as HVAC or security. Outputs may go to one light fixture or could go to every light fixture in the building. There is a lot of flexibility to this approach but there is also a lot of complexity and cost. These systems must be engineered, commissioned, and maintained by skilled people in order to achieve the potential savings. These systems have the capacity to save the most power but in order to be realized, significant investment must be made at the design, installation, and commissioning stages. Not to mention ongoing maintenance as these systems require continuous adjustment by skilled people.
AIOS Dimming™ fills the void between single strategy controls and complex lighting control systems. AIOS Dimming™ monitors human traffic patterns and automatically adjusts light levels to suit usage within a space without the need for ongoing maintenance. It is a simple economical control technology that marries artificial intelligence with occupancy sensing, photo sensing, thermal sensing, and dimming Each sensor has a specific function that gets combined with an algorithm to provide a light level output. Programming is designed to efficiently deliver light based on human traffic patterns and or specific area or individual needs.
AIOS Dimming™ is designed to be used per light fixture or optionally may also be used to control groups of light fixtures. It incorporates a microcontroller that takes inputs from an onboard clock, infrared sensor, occupancy sensor, photo sensor, and thermal sensor. *Alternatively, it could take inputs from independent sensors. Using a software program and an algorithm, the microcontroller decides what light level output to deliver based on inputs it receives from all of the sensors and the duration it takes to adjust from one light level to another.
Programming of the microcontroller occurs through a USB port or through an infrared or radio frequency sensor that receives information from a smart hand held infrared or radio frequency remote control.
Background for the UNIMPO™ Universal Mounting Bracket
Light fixtures are commonly used in a wide variety of indoor applications. These fixtures may be formed from steel or aluminum and house a plurality of linear fluorescent lamps or light emitting diodes. For aesthetic and/or functional reasons, light fixtures may be directly mounted to ceiling and wall surfaces, or suspended down below the ceiling surface. Sometimes it is also desirable to have the fixture angled towards an application area. Examples of this are mechanic workshops where fixtures are angled from the wall towards the engine compartments and swimming pools where lights are angled towards the middle of the pool from the perimeter deck where they can be accessed easily.
To accommodate varying mounting requirements, lighting manufacturers may offer a range of accessories that allow generic products to be installed in multiple applications or they may build specific products that have limited application usage. Lighting installers may also find their own creative means for mounting fixtures when fixtures do not come with specific accessories or are not specifically built for the intended application.
The results of conventional approaches to light fixture mounting are often added cost, lead time, and/or complexity. Customers are often required to pay more and wait longer to accessorize generic products. Installers may also have to endure added cost through on-site modifications, either taking fixtures apart, assembling accessories, or creating an external means of fixation. Therefore, the need exists in the art for a mounting bracket that is economical and allows usage in many applications.
The present invention can satisfy the above-described need by providing a small economical accessory that is easy to use and has many different applications. The UNIMO™ provides an accessory that takes up very little space on the shelf thereby reducing shipping and inventory costs. The product allows usage in many applications: A. Surface Ceiling Mount, B. Surface Ceiling with Adjustable Angle, C. Surface Wall Mount, D. Surface Wall Mount with Adjustable Angle, E. Single Point Pendent Mount from Conduit (with common electrical box), and F. Single Point Pendent Mount with Adjustable Angle.
The universal mounting bracket allows simple installation for one person. The mounting plate gets affixed first and the installer then simply applies screws through the fixture plate and into threaded inserts that are located on the top of the fixture. As the fixture plate is hinged to the mounting plate, the installer can set an angle by adjusting a captive aircraft cable through a tool-less adjustable cable gripper that is mounted to the fixture plate.
The mounting plate has a punch out template that allows mating with common electrical boxes. The installer may secure a box to electrical conduit, or he may secure a hook or a loop to the box which is common in the industry. Power wiring or cabling is routed through the conduit/hook/loop and into the box. The electrical box provides space for wire splicing and the UNIMO™ mounting plate has a common knockout located in the center for fixture power cabling to enter the box. Once the mounting plate is secured to the box, the fixture may be fastened to the fixture plate. Fixture splicing may be applied while the bracket is in the open position. After splicing is completed, the fixture plate is secured to the mounting plate or may be angled if desired.